Simple GetListItems failure

I''ve probably just made a simple SPService mistake, but I am unable to narrow it down. Unfortuntely, the environment is locked down to IE, so don't have my trusty Firefox with Firebug, making troubleshoot more difficult for me. I have this routine:

$().SPServices({
operation: "GetListItems",
async:false,
webURL: "[myUrlHere]/_vti_bin/lists.asmx",
listName: "spec",
completefunc: function(xData, status){
$("#myText").val(xData.responseXML.xml);
var out = $().SPServices.SPDebugXMLHttpResult({
node: xData.responseXML
});
$("#myOutput").val(out);
$("#myStatus").val(status);
}
});
When I dump out the three variables, the xData.responseXML.xml is blank, "out" is <table class='ms-vb' style='margin-left:0px;' width='100%'><tr><td width='100px' style='font-weight:bold'>#document</td><td>&nbsp;</td></tr></table> and the status is "parsererror". Not sure where to go from here to figure out what caused the parsererror. When I run the following code:

You're using webURL incorrectly. In SPServices, you use it to change the context: in other words to call the Web Service for a different site. I've got the operations all wrapped up so that you don't have to specify the asmx page for the Web Service.

Assuming that the "spec' list is in the current site, just remove the webURL option and you should be good to go.

Also, a good debugging trick is just alert the returned XML: alert(xData.responseText);